Safety Joint

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2022-000701 filed on Jan. 5, 2022, the disclosure of which is incorporated herein by reference.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND

1. Field of the Invention

The present invention relates to a safety joint used in a fuel supply device such as a hydrogen gas filling device that supplies fuel such as hydrogen gas, and has a function of separating the fuel supply device and a filling hose in an emergency.

2. Description of the Related Art

In line with the growing awareness of environmental issues in recent years, fuel cell vehicles and hydrogen gas vehicles that use hydrogen gas as fuel, and hydrogen gas filling devices that stably and efficiently fill the tanks of such vehicles with gas fuel are widespread. In such a hydrogen gas filling device, a safety joint is required to reliably and safely separate a hose on the filling device side and a hose on the vehicle side when an unexpected event such as a sudden start of the vehicle or a collision of the vehicle occurs during hydrogen gas filling. As such a safety joint, the applicant has proposed in JP-A-2021-101115 gazette, a safety joint with valve elements having improved sealing property in an entire pressure range from low pressure to high pressure, the safety joint composed of cylindrical plug bodies in which flow passages are formed, and valve elements (valve elements disposed in the flow passages of the plug bodies and pressed against valve seats formed on plug bodies by elastic materials) that are disposed on the same line in the plug bodies and pressed by the elastic materials, the valve elements including first seal means (tapered portions of the valve elements) that are attached to and detached from the valve seats formed on the plug bodies, and second seal means such as O-rings that come into contact with the flow passages formed in the plug bodies.

The safety joint disclosed in the patent document is useful, but since an ultrahigh-pressure hydrogen gas flows at high speed through the flow passage in the safety joint during filling, the O-ring that constitutes the second sealing means in the valve body in the plug body may come off. In addition, if a foreign matter is mixed in the hydrogen gas to be filled, the foreign matter may come into contact with the O-ring and damage the O-ring. Since the safety joint is newly developed, no technique for preventing the O-ring from coming off or being damaged has been proposed at present.

The content of JP-A-2021-101115 gazette is incorporated herein by reference in its entirety.

BRIEF SUMMARY

The present invention has been proposed in view of the above-mentioned problems of the prior art, and the object thereof is to provide a safety joint that can prevent the O-ring from falling off due to the ultra-high pressure hydrogen gas flowing through the flow passage in the safety joint at high speed and from being damaged by the foreign matter coming into contact with the O-ring if the foreign matter is mixed in the hydrogen gas.

A safety joint 100 according to the present invention is characterized by including: a plug body 11 having a flow passage 11 A- 3 with a small inner diameter that is open at one end and a flow passage 11 A- 2 with a large inner diameter that communicates with the flow passage 11 A- 3 with a small inner diameter via a tapered valve seat 11 B; a valve body 12 having a small-diameter portion 12 C and a large-diameter portion 12 A continuous with the small-diameter portion 12 C via a tapered portion 12 B; an elastic body 13 that presses the valve body 12 in a direction of the two flow passages 11 A- 2 , 11 A- 3 in the plug body 11 ; a hollow-shaped cover 15 having a plurality of projections 15 A on an outer peripheral portion 15 B thereof, the cover 15 being disposed in the flow passage 11 A- 2 with a large inner diameter of the plug body 11 so as to surround the valve body 12 ; a first sealing means 12 S 1 formed by the tapered portion 12 B of the valve body 12 coming into contact with the valve seat 11 B of the plug body 11 ; a second sealing means 12 S 2 provided in the small-diameter portion 12 C of the valve body 12 and abutting against an inner wall of the flow passage 11 A- 3 with a small inner diameter of the plug body 11 , wherein when the tapered portion 12 B of the valve body 12 is not seated on the valve seat 11 B of the plug body 11 , the cover 15 surrounds at least a portion of a region from the second sealing means 12 S 2 to the large-diameter portion 12 A side of the valve body 12 , and a flow passage is formed by the adjacent projections 15 A and the outer peripheral portion 15 B of the cover 15 , and an inner peripheral surface of the flow passage 11 A- 2 with a large inner diameter of the plug body 11 .

In the safety joint 100 according to the present invention the small-diameter portion 12 C and the large-diameter portion 12 A of the valve body 12 may be formed in a disc shape; a tip rod-shaped region 12 D continuous with the large-diameter portion 12 A may be provided; an outer diameter of the large-diameter portion 12 A may be larger than an inner diameter of the flow passage 11 A- 3 with a small inner diameter of the plug body 11 ; and the small-diameter portion 12 C can enter the flow passage 11 A- 3 with a small inner diameter of the plug body 11 . In addition, in the present invention, the hollow part of the cover 15 may have a region 15 -C 1 with a large inner diameter formed on the side of the flow passage 11 A- 3 with a small inner diameter of the plug body 11 and a region 15 -C 2 with a small inner diameter formed on the side of the flow passage 11 A- 2 with a large inner diameter of the plug body 11 , and the valve body 12 can enter the region 15 -C 1 with a large inner diameter in the hollow portion of the cover 15 ; and the disk-shaped large-diameter portion 12 A of the valve body 12 cannot enter the region 15 -C 2 with a small inner diameter in the hollow portion of the cover 15 , and the tip rod-shaped region 12 D of the valve body 12 can enter the region 15 -C 2 with a small inner diameter in the hollow part of the cover 15 .

A safety joint 100 - 1 according to the present invention is characterized by including: a plug body 11 having a flow passage 11 A- 3 with a small inner diameter that is open at one end and a flow passage 11 A- 2 with a large inner diameter that communicates with the flow passage 11 A- 3 with a small inner diameter via a tapered valve seat 11 B; a valve body 12 having a small-diameter portion 12 C and a large-diameter portion 12 A continuous with the small-diameter portion 12 C via a tapered portion 12 B; an elastic body 13 that presses the valve body 12 in a direction of the two flow passages 11 A 2 , 11 A- 3 in the plug body 11 ; a first sealing means 12 S 1 formed by the tapered portion 12 B of the valve body 12 coming into contact with the valve seat 11 B of the plug body 11 ; a recess 11 D formed in an inner wall of the flow passage 11 A- 3 with a small inner diameter of the plug body 11 ; a second sealing means 12 S 2 - 1 accommodated in the recess 11 D; and a shutter 16 sliding on the inner wall of the flow passage 11 A- 3 with a small inner diameter of the plug body 11 to open or block the recess 11 D.

According to the present invention with the above-described construction, since a member (cover 15 ) that covers the second sealing means 12 S 2 (for example, the O-ring 14 ) is provided, when the valve is opened, the second sealing means 12 S 2 can be prevented from coming off and breakage due to inflow of a hydrogen gas. Here, when the joint 10 on the filling device side and the joint 20 on the filling hose side are separated, the valve body 12 is seated on the valve seat 11 B to close the valve, so that no hydrogen gas flows through the plugs ( 10 , 20 ). There is no fear that the second sealing means 12 S 2 will fall off, and there is no fear that a foreign substance in the hydrogen gas will damage the second sealing means 12 S 2 . On the other hand, when the joint 10 on the filling device side and the joint 20 on the filling hose side are connected, the valve body 12 is separated from the valve seat 11 B and the valve is open, which causes a hydrogen gas to be supplied to the plugs 10 and 20 at high speed. There is a possibility that the second sealing means 12 S 2 may fall off or be damaged. However, according to the present invention, for example, since the second sealing means 12 S 2 is covered with the cover 15 , the high-pressure hydrogen gas flow does not directly act on the second sealing means 12 S 2 , and the second sealing means 12 S 2 is prevented from coming off. Since no hydrogen gas flow through the cover 15 , even if a foreign matter enters the hydrogen gas, the foreign matter will not damage the second sealing means 12 S 2 .

Here, the cover 15 is hollow and accommodates the valve body 12 in its hollow portion. When the valve body 12 is accommodated in the cover 15 , the hollow portion engages with the valve body 12 , which increases the resistance to fluid of the hollow portion of the cover 15 . As a result, a hydrogen gas does not flow into the hollow portion, but flows through the outer peripheral portion 15 B of the cover 15 with low resistance. No high-speed hydrogen gas flow is generated in the hollow portion of the cover 15 accordingly, and the second sealing means 12 S 2 attached to the valve body 12 is not exposed to the high-speed hydrogen gas flow. As a result, the second sealing means 12 S 2 of the valve body 12 accommodated in the hollow portion of the cover 15 will not fall off due to the hydrogen gas flow. Further, since the velocity of the hydrogen gas flow is slow in the cover internal space 15 C, even if a foreign matter enters and collides with the second sealing means 12 S 2 , the second sealing means 12 S 2 will not be damaged.

Alternatively, according to the present invention, the recess 11 D is formed in the region 11 A- 3 of the hydrogen gas flow passage 11 A- 3 with a small inner diameter, and the second sealing means 12 S 2 is fitted into the recess 11 D to form a sealing mechanism, and the shutter 16 for covering or opening the recess 11 D is provided, and when the safety joint 100 - 1 is connected (normally: open), the shutter 16 covers the O-ring fitting recess 11 D of the hydrogen gas passage. With this, the second sealing means 12 S 2 covered by the shutter 16 is not exposed to the ultrahigh-pressure, high-speed hydrogen gas flow, and the second sealing means 12 S 2 does not come off. Also, even if a foreign matter is mixed into the hydrogen gas, the shutter 16 prevents the foreign matter in the hydrogen gas from coming into contact with the second sealing means 12 S 2 , thereby preventing damage to the second sealing means 12 S 2 .

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory cross-sectional view showing a conventional safety joint.

FIG. 2 is a cross-sectional view of the safety joint shown in FIG. 1 is assembled.

FIG. 3 is an explanatory cross-sectional view showing a state in which the safety joint according to the first embodiment of the present invention is separated, and a valve body is seated on a valve seat to close a valve.

FIG. 4 is side view of the valve body used in the first embodiment.

FIG. 5 is a perspective view of the cover used in the first embodiment.

FIG. 6 is a cross-sectional view of the cover shown in FIG. 5 .

FIG. 7 is an explanatory cross-sectional view showing a state in which the safety joint according to the first embodiment of the present invention is not separated, and the valve body is separated from the valve seat to close the valve.

FIG. 8 is an explanatory cross-sectional view showing a main part of the safety joint according to the second embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate understanding of the embodiments of the present invention, first, an outline of the prior art described in the patent document will be explained with reference to FIGS. 1 and 2 . FIG. 1 shows the safety joint 100 in the prior art, which is composed of a joint 10 on the side of a hydrogen gas filling device and a joint 20 ( FIG. 2 ) on the side of a filling hose. In the attached drawings, illustration of the hydrogen gas filling device and the filling hose is omitted. FIG. 1 shows a state in which the joint 10 is separated from the joint 20 . Although the joint 10 and the joint 20 have similar structural members (plug bodies 1 , 11 , valve bodies 2 , 12 , elastic members 3 , 13 , etc.), the similar structural members of the joints 10 , 20 are indicated by different reference numerals. The valve bodies 2 and 12 and the plug bodies 1 and 11 are made of metal. The joint 20 is constructed similarly to the joint 10 .

In FIG. 1 , the plug body 1 is formed with a flow passage 1 A ( 1 A- 1 to 1 A- 3 ) and a valve accommodating portion 1 C for accommodating a valve body 2 therein. The flow passage 1 A includes a small-diameter region 1 A- 1 communicating with the filling device (existing the top in FIG. 1 ), a large-diameter region 1 A- 2 relating to the valve accommodating portion 1 C, and a small diameter region 1 A- 3 communicating with a filling hose (existing the bottom in FIG. 1 ). The valve accommodating portion 1 C constitutes a part of the flow passage 1 A. In FIG. 1 , in the valve accommodating portion 1 C of the plug body 1 is accommodated the valve body 2 so as to be movable in the flow direction of the flow passage 1 A (vertical direction in FIG. 1 ). A spring 3 is arranged on the filling device side of the valve body 2 (above the valve body 2 in FIG. 1 ). The spring 3 urges the valve body 2 toward the filling hose (downward in FIG. 1 ), so that the valve body 2 is always pressed toward a tapered valve seat 1 B formed at the lower end of the valve accommodating portion 1 C.

In FIG. 1 , the valve body 2 arranged in the valve body accommodating portion 1 C is composed of a large diameter portion 2 A, a tapered portion 2 B, and a small diameter portion 2 C. The tapered portion 2 B is formed at one end (lower end in FIG. 1 ) of the large diameter portion 2 A, and is formed so as to be able to abut against the tapered valve seat 1 B formed in the plug body 1 . A groove 2 G is formed in the small diameter portion 2 C of the valve body 2 , and an O-ring 4 as a sealing member is accommodated in the groove 2 G. The small diameter portion 2 C of the valve body 2 can be inserted into the region 1 A- 3 on the filling hose side (lower side in FIG. 1 ) of the flow passage 1 A, and when the joint 10 on the filling device side and the joint 20 on the filling hose side are separated (the case shown in FIG. 1 ), the small diameter portion 2 C is inserted into the region 1 A- 3 . On the other hand, when the joint 10 and the joint 20 are connected (in the case of FIG. 2 ), the small diameter portion 2 C is located on the filling device side (above in FIG. 1 ) from the region 1 A- 3 , and is not inserted in the region 1 A- 3 .

In FIG. 1 , the tapered valve seat 1 B formed in the valve accommodating portion 1 C and the tapered portion 2 B formed at one end of the large diameter portion 2 A of the valve body 2 constitute a first sealing means 2 S 1 . When the tapered portion 2 B of the valve body 2 is seated on the valve seat 1 B of the plug body 1 , the valve (first sealing means 2 S 1 ) is closed, and the state shown in FIG. 1 is obtained. On the other hand, when the tapered portion 2 B of the valve body 2 separates from the valve seat 1 B of the plug body 1 , the first sealing means 2 S 1 is opened and enters the state shown in FIG. 2 . Since both the valve body 2 and the plug body 1 are made of metal, when the valve body 2 is seated on the valve seat 1 B, a metal seal is formed to ensure airtightness. In particular, when the fluid fuel is at high pressure, the first sealing means 2 S 1 exhibits excellent sealing performance as well as pressure resistance.

In FIG. 1 , the O-ring 4 accommodated in the groove 2 G of the small diameter portion 2 C of the valve body 2 contacts the inner wall surface of the region 1 A- 3 on the hose side of the flow passage 1 A when the joint 10 and the joint 20 are separated, and the O-ring 4 and the inner wall surface of the region 1 A- 3 constitute a second sealing means 2 S 2 . The contact of the O-ring 4 with the region 1 A- 3 allows the second sealing means 2 S 2 to exhibit sealing performance. On the other hand, when the small diameter portion 2 C moves toward the valve accommodating portion 1 C of the plug body 1 and the O-ring 4 does not come into contact with the filling hose side region 1 A- 3 (state shown in FIG. 2 ), the second sealing means 2 S 2 cannot exhibit sealability. The contact (or contact in a sliding state) of the inner wall surface of the filling hose-side region 1 A- 3 and the O-ring 4 of the second sealing means 2 S 2 improve the sealing performance at low pressure.

When the safety joint 100 shown in FIG. 2 is assembled, that is, when the joint 10 on the filling device side and the joint 20 on the filling hose side are connected, there is a rod 8 between the joint 10 and the joint 20 . The end portion of the rod 8 on the side of the filling device (upper in FIG. 2 ) presses the valve body 2 on the side of the filling device, pushing the valve body 2 against the elastic force of the spring to separate the valve body 2 from the valve seat 1 B. On the other hand, the end of the rod 8 on the filling hose side (lower in FIG. 2 ) presses the valve body 12 on the filling hose side to separate the valve body 12 from a valve seat 11 B. As a result, the first sealing means 2 S 1 and 12 S 1 (a valve constituted by the tapered portion 2 B of the valve body 2 and the valve seat 1 B and a valve constituted by the tapered portion 12 B of the valve body 12 and the valve seat 11 B) are opened. At the same time, in the second sealing means 2 S 2 and 12 S 2 , since the small diameter portion 2 C is not inserted in the region 1 A- 3 , and the small diameter portion 12 C is not inserted in the region 11 A- 3 , the O-ring 4 and the O-ring 14 are not in contact with the inner wall surfaces of the regions 1 A- 3 , 11 A- 3 , resulting in no sealing functions. The hydrogen gas consequently can flow from the filling device side to the filling hose side (fuel tank side of the vehicle) through the safety joint 100 (flow passages 1 A and 11 A of the joints 10 and 20 ) without being sealed.

When a hydrogen gas filling hose (not shown) is subjected to a tensile force greater than expected during hydrogen gas filling, the joint 10 on the filling device side and the joint 20 on the filling hose side are separated by a known mechanism (not shown). When the joint 10 and the joint 20 are separated, the rod 8 is disengaged from the joints 10 and 20 , so that the valve bodies 2 and 12 are pressed by the springs 3 and 13 , respectively to move toward the valve seats 1 B and 11 B of the plug bodies 1 and 11 , the tapered portions 2 B and 12 B of the valve bodies 2 and 12 are seated on the valve seats 1 B and 11 B, and the first sealing means 2 S 1 and 12 S 1 are closed. When the joint 10 and the joint 20 are separated, the small diameter portions 2 C and 12 C of the valve bodies 2 and 12 are inserted into the regions 1 A- 3 and 11 A- 3 , so that the second sealing means 2 S 2 constituted by the O-ring 4 and the filling hose side region 1 A- 3 and the second sealing means 12 S 2 constituted by the O-ring 14 and the filling hose side region 11 A- 3 exhibit sealing functions. As a result, when the joint 10 and the joint 20 are separated, the hydrogen gas (fluid fuel) on the filling device side is prevented from flowing out through the joint 10 , and the hydrogen gas on the filling hose side is prevented from flowing out through the joint 20 .

Next, the first embodiment of the present invention will be described with reference to FIGS. 3 to 7 . As described above, during filling, since an ultra-high pressure hydrogen gas flows at high speed through the flow passages 1 A- 2 and 11 A- 2 in the safety joint, there is a risk that the O-rings 4 and 14 constituting the second sealing means may fall off. Moreover, if a foreign matter is mixed in the hydrogen gas to be filled, the foreign matter may come into contact with the O-rings 4 and 14 and damage them. In the present invention, a member is provided to cover the O-rings 4 and 14 when the valve is opened, thereby preventing the O-rings 4 and 14 from coming off or being damaged due to inflow of hydrogen gas.

When the outline of the prior art was explained with reference to FIGS. 1 and 2 , the joint 10 on the filling device side was illustrated and explained, but in the explanation of the first embodiment shown in FIGS. 3 to 7 , the joint 20 will be illustrated and explained. As mentioned above, the joint 10 and the joint 20 have similar components. The joint 10 or 20 according to the first embodiment includes a cover 15 (a structure not provided in the prior art of FIGS. 1 and 2 ) as a member that covers the O-rings 4 and 14 when the valve is opened. Since the cover 15 is provided and functions, the shape of the valve body 12 ( 2 ), etc. in the first embodiment shown in FIGS. 3 to 7 are different from those of the prior art show in FIGS. 1 and 2 . However, the same reference numerals as in FIGS. 1 and 2 are used for the reference numerals of the members corresponding to the prior art shown in FIGS. 3 to 7 . FIGS. 3 to 7 show the members on the side of the joint 20 , and do not show the members on the side of the joint 10 .

FIG. 3 shows a state in which the joint 10 on the side of the filling device (not shown) and the joint 20 on the side of the filling hose are separated. In FIG. 3 , the plug body 11 of the joint 20 is formed with a flow passage 11 A ( 11 A- 1 to 11 A- 3 ) and a valve body accommodating portion 11 C, and a valve body 12 is accommodated in the valve body accommodating portion 11 C. The flow passage 11 A includes a small-diameter region 11 A- 3 communicating with the filling device side (upper side in FIG. 3 ), a large-diameter region 11 A- 2 forming the valve accommodating portion 11 C, and a small-diameter region 11 A- 1 communicating with the filling hose side (lower side in FIG. 3 ). The valve accommodating portion 11 C is in communication with a filling device (not shown) through a region 11 A- 3 , and is in communication with a filling hose (not shown) through a region 11 A- 1 . The direction of hydrogen gas flow is indicated by the arrow Y in FIGS. 3 and 7 . In FIG. 3 in which the joint 10 on the filling device side (not shown) is separated, no hydrogen gas flows, and the arrow Y indicates an imaginary direction of hydrogen gas flow when the hydrogen gas flows. A hydrogen gas flows from the joint 10 (plug body 1 , see FIG. 1 ) on the filling device side to the joint 20 on the filling hose side (plug body 11 ) (in the direction of the arrow Y 1 ), and flows from the filling hose side coupling 20 (plug body 11 ) to the filling hose (not shown) (arrow Y 2 ). In the joint 10 (see FIG. 1 ), the direction of hydrogen gas flow is opposite to the directions Y 1 and Y 2 shown in FIG. 3 .

In FIG. 3 , the valve body 12 is accommodated in the valve body accommodating portion 11 C of the plug body 11 so as to be movable in the direction of the flow passage 11 A (longitudinal direction of the flow passage 11 A: vertical direction in FIG. 3 ). A spring 13 is arranged on the filling hose side (lower in FIG. 3 ) of the valve body 12 . The spring 13 urges the valve body 12 toward the filling device (upward in FIG. 3 ), so that the valve body 12 is always pressed toward the tapered valve seat 11 B formed at the upper end of the valve body accommodating portion 11 C. The valve body 12 and the plug body 11 are made of metal. A groove 12 G is formed in the small diameter portion 12 C of the valve body 12 , and an O-ring 14 as a sealing member is fitted (accommodated) in the groove 12 G. The small-diameter portion 12 C of the valve body 12 can be inserted into a region 11 A- 3 on the filling device side (upper side in FIG. 3 ) of the flow passage 11 A, and when the joint 10 and the joint 20 separate from each other as shown in FIG. 3 , the small diameter portion 12 C is inserted into the region 11 A- 3 , and the valve body 12 is seated on the tapered valve seat 11 B formed at the upper end of the valve body receiving portion 11 C. On the other hand, in the case shown in FIG. 7 , that is, when the joint 10 on the filling device side and the joint 20 on the filling hose side are coupled, the small diameter portion 12 C is not inserted into the region 11 A- 3 , and is located on the filling hose side (lower in FIG. 3 ) of the region 11 A- 3 .

As described above, the valve body 12 is positioned in the valve body accommodating portion 11 C (region 11 A- 2 ) in FIG. 3 . The details of the valve body 12 are shown in FIG. 4 . The valve body 12 will be described below with reference to FIGS. 3 and 4 . The valve body 12 includes a large diameter portion 12 A, a tapered portion 12 B formed at one end of the large diameter portion 12 A and abutting against the valve seat 11 B, and a small diameter portion 12 C extending upward in FIG. 4 from the tapered portion 12 B. Further, the valve body 12 has a tip rod-shaped region 12 D near the end (front end side) on the side (lower side in FIG. 4 ) separated from the small diameter portion 12 C. The large-diameter portion 12 A is continuous with the tip rod-shaped region 12 D via a stepped portion, and has a disc shape. The outer diameter of the large diameter portion 12 A is larger than the inner diameter of the region 11 A- 3 . The small diameter portion 12 C is continuous with the large diameter portion 12 A via the tapered portion 12 B, and has a smaller outer diameter than the large diameter portion 12 A. The outer diameter of the small diameter portion 12 C is smaller than the inner diameter of the region 11 A- 3 , so that it can enter the region 11 A- 3 . A tapered portion 12 DT is formed on the tip side (filling hose side, lower side in FIGS. 3 and 4 ) of the tip rod-shaped region 12 D in order to reduce the resistance to the hydrogen gas flow. Although not shown, the small diameter portion 12 C of the valve body 12 can be tapered at the filling device side end (upper side in FIG. 3 ) to reduce resistance to reverse hydrogen gas flow.

In FIGS. 3 and 4 , the tapered portion 12 B formed at one end of the large diameter portion 12 A of the valve body 12 and the valve seat 11 B formed in the plug body 11 constitute a first sealing means 12 S 1 . When the tapered portion 12 B of the valve body 12 is seated on the valve seat 11 B of the plug body 11 , the first sealing means 12 S 1 is closed (the state shown in FIG. 3 ). On the other hand, when the tapered portion 12 B of the valve body 12 is separated from the valve seat 11 B of the plug body 11 , the first sealing means 12 S 1 is opened (the state shown in FIG. 7 ). The first sealing means 12 S 1 , which is composed of the valve body 12 and the plug body 11 both made of metal, forms a metal seal when the tapered portion 12 B of the valve body 12 is seated on the valve seat 11 B. In particular, when the fluid fuel is at high pressure, it exhibits excellent pressure resistance as well as excellent sealing performance.

In FIGS. 3 and 4 , the O-ring 14 accommodated in the groove 12 G formed in the small-diameter portion 12 C of the valve body 12 will be in contact with the inner wall surface of the region 11 A- 3 of the flow passage 11 A on the filling device side when the joint 10 ( FIG. 1 ) on the filling device side and the joint 20 on the filling hose side are separated (the state shown in FIG. 3 ). The O-ring 14 and the inner wall surface of the region 11 A- 3 constitute the second sealing means 12 S 2 . When the O-ring 14 contacts with the inner wall surface of the region 11 A- 3 , the sealing performance is exhibited, and the second sealing means 12 S 2 is closed. FIG. 4 shows the state in which the O-ring 14 is incorporated into the valve body 12 . On the other hand, when the small diameter portion 12 C moves toward the valve accommodating portion 11 C of the plug body 11 and the O-ring 14 does not contact with the filling device side region 11 A- 3 (the state shown in FIG. 7 ), the second sealing means 12 S 2 is also in an open state and does not exhibit sealing performance. In the second sealing means 12 S 2 , the contact (or sliding contact) between the inner wall surface of the region 11 A- 3 on the filling device side and the O-ring 14 improves the sealing performance at low pressure.

In FIG. 3 , the valve body 12 located in the valve body accommodating portion 11 C (the region 11 A- 2 ) is surrounded by a hollow cover 15 . Details of the cover 15 are shown in FIGS. 5 and 6 . The configuration and function of the cover 15 will be described with reference to FIGS. 3 to 6 . As shown in FIG. 6 , the cover 15 has hollow portions 15 C ( 15 C- 1 , 15 C- 2 ). The hollow portions 15 C- 1 and 15 C- 2 may be collectively referred to as the hollow portion 15 C. As clearly shown in FIG. 6 , the hollow portion 15 C of the cover 15 has a region 15 C- 1 with a large inner diameter and a region 15 C- 2 with a small inner diameter. The region 15 C- 1 with a large inner diameter is formed on the side of the region 11 A- 3 with a small inner diameter of the passage in the assembled states shown in FIGS. 3 and 7 . The disc-shaped large-diameter portion 12 A of the valve body 12 can enter the region 15 C- 1 having a large inner diameter. In the assembled states of FIGS. 3 and 7 , the region 15 C- 2 with a smaller inner diameter is formed on the side of the region 11 A- 2 with a larger inner diameter of the passage. The large-diameter portion 12 A of the valve body 12 cannot enter the region 15 C- 2 with a small inner diameter. However, the tip rod-shaped region 12 D of the valve body 12 can enter the region 15 C- 2 with a small inner diameter.

At least a portion of the valve body 12 is accommodated in the hollow portion 15 C of the cover 15 . That is, when the tapered portion 12 B of the valve body 12 is separated from the valve seat 11 B and is not seated on the valve seat 11 B, that is, when the valve (first sealing member 12 S 1 ) is opened (in the case of FIG. 7 ), the region 15 C- 1 having a large inner diameter surrounds at least a portion of the region on the side of the large diameter portion 12 A of the valve body 12 from the second sealing means 12 S 2 (O-ring 14 ). On the other hand, when the tapered portion 12 B of the valve body 12 is seated on the valve seat 11 B, that is, when the valve is closed (in the case of FIG. 3 ), the region 15 C- 1 having a large inner diameter in the hollow portion 15 C surrounds at least a portion of the large diameter portion 12 A and the small diameter portion 12 C of the valve body 12 .

As shown in FIG. 5 , a plurality of projections 15 A (guides or fins) is formed on the outer peripheral portion 15 B of the cover 15 , each of the projections 15 A extending substantially over the entire length of the cover 15 in the direction of the flow passage. A hydrogen gas passage is formed by the projections 15 A, the outer peripheral portion 15 B of the cover 15 , and the inner peripheral surface of the region 11 A- 2 having the larger inner diameter of the passage. A hydrogen gas flows through the hydrogen gas passage when the joint 10 on the filling device side and the joint 20 on the filling hose side are coupled as shown in FIG. 7 . In the case shown in FIG. 3 , that is, when the joint 10 and the joint 20 are separated, no hydrogen gas flows in the hydrogen gas flow passage formed by the protrusions 15 A, the outer peripheral portion 15 B of the cover 15 , and the inner peripheral surface of the region 11 A- 2 . Although not shown in FIGS. 5 and 6 , guide grooves for guiding the projections 15 A of the cover 15 when the cover 15 moves in the flow passage direction may be formed on the inner peripheral surface of the region 11 A- 2 where the inner diameter of the flow passage 11 A is large. Such guide grooves may be omitted. In other words, the cover 15 may be rotatable inside the region 11 A- 2 of the flow passage 11 A of the plug body 11 having a large inner diameter. Also, only a portion of the protrusion 15 A needs to fit into the guide groove, and not all the protrusions 15 A need to fit into the guide grooves.

In the illustrated first embodiment, when the valve is closed as shown in FIG. 3 , the stopper 15 D ( FIG. 6 ) formed at the end portion of the cover 15 on the filling device side is engaged with the ceiling of the region 11 A- 2 having the large inner diameter on the side of the filling device to form a space K ( FIG. 3 ). The space K may be omitted, and the end of the cover 15 on the side of the filling device may contact the ceiling of the region 11 A- 2 . In other words, unless the cover 15 interferes with the ceiling portion of the region 11 A- 2 with a large inner diameter on the side of the filling device and does not cover the O-ring 14 , the presence or absence of the space K shown in FIG. 3 doesn't matter. As shown in FIGS. 5 and 6 , the cover 15 has a tapered portion 15 E for reducing resistance at the end on the filling hose side (diagonally lower right in FIG. 5 : lower in FIG. 6 ) as assembled. Although not shown, the end of the cover 15 on the filling device side (diagonally upper left in FIG. 5 : upper in FIG. 6 ) as assembled can also be formed with a taper for reducing resistance. The tapered portion 15 E described above is effective because it faces the flow of hydrogen gas when applied to the cover of the joint 10 on the filling device side. On the other hand, the taper not shown is effective in facing the hydrogen gas flow when applied to the cover 15 of the joint 20 on the filling hose side.

FIG. 7 shows the joint 20 on the filling hose side when the joint 10 on the filling device side and the joint 20 on the filling hose side are connected. The directions in which hydrogen gas flows in FIG. 7 are indicated by arrows Y (Y 1 , Y 2 ). In FIG. 7 , the rod 8 is interposed between the joint 10 and the joint 20 , the end of the rod 8 on the filling hose side (lower in FIG. 7 ) pressing the valve body 12 on the filling hose side against the elastic force of the spring 13 to separate the tapered portion 12 B of the valve body 12 from the valve seat 11 B. Although not shown, the end of the rod 8 on the side of the filling device (upper in FIG. 7 ) presses the valve body 2 (not shown in FIG. 7 ) of the joint 10 on the side of the filling device, in the joint 10 also the rod 8 separates the tapered portion 2 B of the valve body 2 from the valve seat 1 B ( FIGS. 1 and 2 ). As a result, the first sealing means 12 S 1 (a valve constituted by the tapered portion 12 B of the valve body 12 and the valve seat 11 B) of the joint 20 on the filling hose side is opened, and the first sealing means 2 S 1 of the joint 10 (not shown) on the filling device side is opened.

In FIG. 7 , when the first sealing means 12 S 1 is opened, the small diameter portion 12 C of the second sealing means 12 S 2 of the joint 20 on the filling hose side is not inserted into the region 11 A- 3 and the O-ring 14 is not in contact with the inner wall surface of the region 11 A- 3 , so that the O-ring 14 does not perform its sealing function. Similarly, the O-ring 4 of the second sealing means 2 S 2 of the joint 10 ( FIGS. 1 and 2 ) on the filling device side (not shown) does not contact with the inner wall surface of the region 1 A- 3 , so that it does not exhibit its sealing function. Since the first sealing means 12 S 1 and 2 S 1 are in open states and the second sealing means 12 S 2 and 2 S 2 do not exhibit sealing functions, a high-pressure hydrogen gas flows from the hydrogen gas filling device side through the safety joint 100 (flow passages 1 A and 11 A of the joints 10 , 20 ) to the filling hose side (fuel tank side of a vehicle).

In the state shown in FIG. 7 , the region 15 C- 1 having a large inner diameter in the hollow portion 15 C of the cover 15 surrounds at least a portion of an area on the side of the large diameter portion 12 A of the valve body 12 from second sealing means 12 S 2 (O-ring 14 ). The second sealing means 12 S 2 (O-ring 14 ) can be protected accordingly against a high-pressure hydrogen gas flow passing through the flow passage formed in the outer peripheral portion 15 B of the cover 15 . The function of protecting the second sealing means 12 S 2 (O-ring 14 ) by the cover 15 will be described later.

As shown in FIG. 2 , there is a possibility that the O-ring 14 may fall off or be damaged when the valve is opened and high pressure hydrogen gas flows into the flow passage 11 A. However, according to the first embodiment shown in FIGS. 3 to 7 , the O-ring 14 accommodated in the recess 12 G of the valve plug 12 is surrounded and protected by the cover 15 , which prevents the O-ring 14 from falling off out of the groove 12 G. In addition, as will be described later, hydrogen gas does not flow in the internal space 15 C of the cover 15 , even if a foreign matter enters, the foreign matter will not contact the O-ring 14 , and the O-ring 14 will not be damaged.

The flow of hydrogen gas in the cover 15 will be described. In FIG. 7 in which the valve is open, the valve body 12 and the cover 15 are in contact with each other as indicated by the symbol F. Specifically, the end surface of the large-diameter portion 12 A of the valve body 12 on the side of the tip rod-shaped region 12 D and the stepped portion of the hollow portion 15 C of the cover 15 come into contact with each other at the location indicated by the symbol F. When the end surface of the large diameter portion 12 A of the valve body 12 and the stepped portion of the cover 15 contact with each other, a part of the valve body 12 is accommodated inside the cover 15 (hollow portion 15 C). With this, an annular space is formed between the outer surface of the valve body 12 and the inner surface of the hollow portion 15 C of the cover 15 , the radial distance in the annular space is small and the resistance to fluid is large, which makes it difficult for hydrogen gas to flow. On the other hand, the resistance to fluid of the hydrogen gas flow passages radially outward of the cover 15 (the flow passages configured by the projections 15 A, the outer peripheral portion 15 B and the inner peripheral surface of the region 11 A- 2 having a large inner diameter) is much smaller in comparison to the resistance to fluid in the hollow portion 15 C of the cover 15 . Therefore, the hydrogen gas hardly flows downstream side (filling hose side) of the portion indicated by the symbol F, and flows through the passage configured by the adjacent projections 15 A of the cover 15 , the outer peripheral portion 15 B and the inner peripheral surface of the region 11 A- 2 having a large inner diameter of the flow passage.

A hydrogen gas hardly flows into the hollow portion 15 C inside the cover 15 , which has high resistance to fluid. However, the flow rate of hydrogen gas flowing through the hollow portion 15 C of the cover 15 does not necessarily have to be zero (0). The resistance to fluid of the hollow portion 15 C is more significant than that of the flow passage outside the cover 15 (the hydrogen gas flow passage composed of the adjacent projections 15 A, the outer peripheral portion 15 B, and the inner peripheral surface of the region 11 A- 2 having a large inner diameter of the flow passage) should be as large as possible. In addition, a sealing material may be arranged at a contact point indicated by symbol F (the point at which the end surface of the large-diameter portion 12 A of the valve body 12 and the stepped portion of the hollow portion 15 C of the cover 15 contact) so that the flow rate of hydrogen gas through the hollow portion 15 C of the cover 15 can be zero.

The flow rate of the hydrogen gas flowing through the hollow portion 15 C of the cover 15 is small (or does not flow), and the hydrogen gas flows through the flow passage with low resistance on the outer peripheral side of the cover 15 . As a result, the flow velocity of the hydrogen gas flow in the hollow portion 15 C of the cover 15 becomes very low or zero, and the O-ring 14 of the valve body 12 accommodated in the hollow portion 15 C of the cover 15 will not fall off due to the hydrogen gas flow flowing through the hollow portion 15 C. In the hollow portion 15 C, since the flow velocity of the hydrogen gas flow becomes slow (or becomes zero), even if the hydrogen gas mixed with a foreign matter collides with the O-ring 14 , the O-ring 14 will not be damaged.

A second embodiment of the present invention will now be described with reference to FIG. 8 . In the safety joint 100 - 1 of the second embodiment shown in FIG. 8 , grooves (concave portions) are formed on the hydrogen gas flow passages 1 A and 11 A in the plug bodies 1 and 11 of the filling device side joint 10 and the filling hose side joint 20 , respectively are formed, and the O-rings 4 and 14 are fitted in the grooves (recesses). In that respect, it differs from the first embodiment shown in FIGS. 3 to 7 . In the second embodiment shown in FIG. 8 , redundant description of the same configuration as that of the first embodiment shown in FIGS. 3 to 7 will be avoided. Similar to the first embodiment of FIGS. 3 - 7 , the second embodiment of FIG. 8 will be described with respect to the joint 20 on the filling hose side. The joint 10 on the filling device side is not shown.

In FIG. 8 , a concave portion 11 D (groove) is formed in the inner wall of the region 11 A- 3 of the filling hose side plug body 11 where the inner diameter of the passage is small. An O-ring 14 constituting a second sealing means is fitted (or housed) in the recess 11 D. When the joint 20 on the filling hose side and the joint 10 on the filling device side are separated and the valve is closed (the state shown in FIG. 3 of the first embodiment), although the O-ring 14 and the outer circumference of the valve body 12 (small diameter portion 12 C) constitutes the second sealing means 12 S 2 - 1 , the second sealing means 12 S 2 - 1 is not formed in FIG. 8 showing the valve open state. The region 11 A- 3 having a small inner diameter of the flow passage 11 A is provided with a shutter 16 that slides on the inner wall surface of the region 11 A- 3 to open or close the recess 11 D. The shutter 16 is interlocked with the axial movement of the valve body 12 , and when the valve is opened (the state of FIG. 7 of the first embodiment: the state where the joint 20 on the filling hose side and the joint 10 on the filling device side are connected), the shutter 16 closes (blocks) the recess 11 D, when the valve is closed (the state shown in FIG. 3 of the first embodiment), the shutter 16 opens the recess 11 D. In FIG. 8 , the reference numeral 16 (A) indicates the shutter 16 positioned to close the recess 11 D when the valve is opened. The reference numeral 16 (B) denotes the shutter 16 positioned to open the recess 11 D when the valve is closed. As a mechanism for moving the shutter 16 (for example, in conjunction with movement of the valve body 12 ), a conventionally known mechanism can be adopted.

In FIG. 8 , when the joints 10 and 20 on the filling device side and the filling hose side are connected (when the valve is open: the state of FIG. 7 of the first embodiment), since the joint recess 11 D, for the O-ring 14 , in the region 11 A- 3 of the flow passage 11 A is closed by the shutter 16 at position 16 (A), the O-ring is fitted in the recess 11 D is protected. As a result, the O-ring 14 is prevented from falling off by the high-pressure, high-speed hydrogen gas flowing through the flow passage 11 A, and even if a foreign matter is mixed in the hydrogen gas, the O-ring 14 will not come into contact with the foreign matter and will not be damaged. On the other hand, when the joints 10 and 20 are separated (when the valve is closed: the state shown in FIG. 3 of the first embodiment), in conjunction with the valve body 12 moving to close the valve, the shutter 16 is moved to the position shown by 16 (B) to open the recessed part 11 D, and to expose the O-ring 14 . The exposed O-ring 14 cooperates with the outer peripheral surface of the small-diameter portion 12 C of the valve body 12 to serve as the second sealing means 12 S 2 - 1 and exhibit sealing performance at low pressure. Other configurations and effects of the second embodiment shown in FIG. 8 are the same as those of the first embodiment shown in FIGS. 3 to 7 .

It should be noted that the illustrated embodiments are merely examples and are not intended to limit the technical scope of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

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• 1 , 11 plug bodies • 1 A, 11 A flow passages • 1 A- 2 , 11 A- 2 regions with large inner diameter • 1 A- 3 , 11 A- 3 regions with small inner diameter • 1 B, 11 B valve seats • 1 C, 11 C valve accommodating portions • 1 D, 11 D concave portions • 2 , 12 valve bodies • 2 A, 12 A large diameter portions of valve bodies • 2 B, 12 B tapered portions of valve bodies • 2 C, 12 C small diameter portions of valve bodies • 2 D, 12 D tip rod-shaped regions • 2 S 1 , 12 S 1 first sealing means • 2 S 2 , 12 S 2 , 2 S 2 - 1 , 12 S 2 - 1 second sealing means • 3 , 13 elastic members • 4 , 14 O-rings • 15 cover • 15 A projection (guides or fins) • 15 B outer peripheral portion of covers • 15 C hollow portions of cover • 15 C- 1 hollow portion with large inner diameter of cover • 15 C- 2 hollow portion with small inner diameter of cover • 16 shutter • 100 , 100 - 1 safety joints